Why would a PCIe x16 slot be limited to PCIe x1 card?

PCI vs PCIe Slot · PCI-E x16 slot: It is 89mm long and has 164 pins It is often used for graphics cards and backward compatible with x1 x4

The new Mac Pro with M2 Ultra combines our most powerful Apple silicon yet with PCIe expansion for the ultimate in workstation-class performance

pcie 30 x4 slot PCIe slots come in different physical configurations: x1, x4, x8, x16, x32 The number after the x tells you how many lanes (how data travels to

pcie slot configuration gen1 gen2 gen3 A PCI-E x1 slot, which has just one lane, takes up almost no space on the motherboard And a 32-lane PCI-E x32 slot is similar to PCI-X slots in